Showing results for 
Search instead for 
Did you mean: 

VSS/VSL no cdp enable - why?

Michael Berry
Level 1
Level 1

I'm wondering if anyone can explain the underlying technical reason why cdp is disabled on VSL links without an option to re-enable.  I'm looking for a technical reason - is there some type of conflict that is being avoided and why does it only apply to cdp...

1 Reply 1

Level 1
Level 1


I was wondering too when configuring our 6807s for VSS. Maybe below will give some inputs.

VSL Characteristics

The VSL port channel is treated as an internal systems link. As a result, its configuration, resiliency, mode of operation, quality of service (QoS), and traffic load sharing follow a set of rules that are specific to VSL. This section covers configuration requirements relating to those rules. The logical port channel and its member link both have distinct sets of restrictions.

VSL protocol(VSLP) runs VSL, that follows its own sets of rules to manage the link.

VSS Terminology

  • Virtual Switch Link (VSL)—A special port channel required to bundle two physical switches into one virtual switch.

  • VSL Protocol (VSLP)—Runs between active and standby switch over the VSL, and has two components: LMP and RRP

    • Link Management Protocol (LMP)—Runs over each individual link in VSL

    • Role Resolution Protocol (RRP)—Runs on each side (each peer) of the VSL port channel

***Please rate and mark the comment correct if you find it helpful. Thanks***

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Review Cisco Networking products for a $25 gift card